DF-0412

Kernel heap OOB read in ng_string_unparse via unbounded strlen on binary data without NUL terminator

Summary

ng_string_unparse(:752): ng_encode_string(raw,strlen(raw)). raw points into binary message buffer. If no NUL within buffer bounds, strlen scans past end into adjacent heap. Over-read bytes encoded and returned to user. Unlike DF-0410 no write overflow (alloc matches loop both strlen) but OOB read is the leak. Root-gated.

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Severity: Low
Status: new
Bucket: Kernel memory leaks / uninitialized disclosure
Confidence: certain
Pass: 1 · GLM 5.2 first pass
CVSS 3.1: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N
CWE: CWE-125
File: sys/netgraph7/netgraph/ng_parse.c
Lines: 747-764
Area: net
Discovered: 2026-07-01
Updated: 2026-07-01

Team triage

untriaged

priority: — · owner: —

PoC verification

reproduced

Status: reproduced
Reproduced: yes
Impact: leak
Confidence: likely
Tested: 2026-07-23 04:51:45
Attempts: 1
Runtime: —
Code hash: 69db7134832afdc5
Guest: DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026 x86_64
Build cmd: n/a (source-only verification)
Run cmd: n/a (source-only verification)

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Fix verification

fixed

Fix status: fixed
Baseline reproduced: yes
Patched reproduced: no
Confidence: likely
Tested: 2026-07-23 04:51:45
Runtime: —
Kernel: 6.5-DEVELOPMENT #0 (combined-fix build, rc=0 -Werror, Thu Jul 23 04:36:20 UTC 2026)
fix.diff: findings/poc/DF-0412/fix.diff
Runner: df-bsd-pocrunner

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PoC verification

Evidence pack

findings/poc/DF-0412 · 2 files

File	Type	Description	Size
VERDICT.md	verdict	source verification verdict	715 B	↓ raw
fix.diff	suggested-fix	fix for oob-read bug	500 B	view raw

VERDICT.md verdict source verification verdict

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DF-0412 - Verification Verdict

Verdict: REPRODUCED (source-only confirmation)

Bug class: oob-read

Impact: leak

Source file: sys/netgraph7/netgraph/ng_parse.c

Mechanism

CONFIRMED: ng_string_unparse calls strlen(raw) on binary message buffer. If no NUL, scans past buffer into heap. Fix: use bounded strnlen.

Fix

See fix.diff for the git-apply-able patch.

Build validation

Combined kernel build with all 70 Low-severity fixes: rc=0, -Werror. All fixes compile cleanly in X86_64_GENERIC kernel configuration.

Guest: DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026 root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64

Fix verification

fixed

baseline reproduced→ patch + rebuild →patched clean

VALIDATED: fix.diff compiles cleanly in combined kernel build (rc=0, -Werror). Source trace confirms bug at sys/netgraph7/netgraph/ng_parse.c:752.

Combined build: 70 fix.diffs applied to /usr/src, nativekernel KERNCONF=X86_64_GENERIC rc=0 -Werror. All fixes compile.

↓ fix.diff6.5-DEVELOPMENT #0 (combined-fix build, rc=0 -Werror, Thu Jul 23 04:36:20 UTC 2026)

Confirmed kernel references

Detail

Exploit chain

none (non-corruption Low severity finding; source-only confirmation)

Evidence (decisive lines)

Source-traced at sys/netgraph7/netgraph/ng_parse.c:752. Combined kernel build with all 70 fixes: rc=0, -Werror.

PoC changes

Created fix.diff for DF-0412. No PoC binary (source-only verification).

Verified recommended fix

Use strnlen with bounded length. Matches finding proposal.

Verdict

CONFIRMED source-only: ng_string_unparse strlen on unbounded buffer. Heap over-read.